A North council has apologised after unauthorised letters were sent to residents asking for private information.

The letters, on the local authority's letterheaded paper, asked for National Insurance numbers.

They also enquired about the names and account numbers of fuel suppliers and details of social security benefits.

But Castle Morpeth Council in Northumberland has admitted that the letters should never have been sent.

Officials say they were wrongly posted out on the council's behalf by a company carrying out insulation work on local authority housing.

But the wording was not checked by the council in advance.

And the distribution list included some owner-occupiers who would not have qualified for home improvement grants.

Now the company that sent the letters has been rapped by a furious council boss whose name appeared on the letter.

And the firm has admitted that it did not even need to know all the information it had asked for.

Trevor Walker, Castle Morpeth's director of community and customer services, said: "I have told the company in the strongest possible terms that I am not happy.

"It was an administrative mistake but it was an administrative mistake that should not have happened.

"Sending the letter out to owner-occupied properties was a mistake and sending it out without my approval was a mistake.

"If this letter had come through my door I would not have been happy."

Mr Walker said the letter did not explain the council initiative to improve housing stock in sufficient detail.

He said: "I can understand why recipients would be concerned about being asked for personal information.

"The letter does not explain what the council is trying to achieve. It reads as if it is a response to an inquiry."

Mr Walker has withdrawn the letter until officials can draft another one . . . and this time it will be done correctly.

The offending letters were sent after the council obtained funding from gas and electricity supplier npower for a project to improve energy efficiency standards in its 800 houses.

Npower provided #108,000 and the council chipped in #72,000.

The letters were posted by npower agents KNW Energy Conservation, of Newcastle, who are to carry out the work at no cost to tenants.

A spokeswoman for KNW said: "We sent them out in good faith. I can assure you there is nothing underhand.

"We have since apologised and put an immediate hold on the scheme until we can get the right addresses.

"We were all trying to get it going but we were not in sync with each other.

"I would say we jumped the gun a bit in an effort to help people who will benefit from the scheme."

I wanted to know why the company asked for private information, including the name and address of each household's current energy supplier . . . especially after I found out that the insulation scheme applies to all council tenants, irrespective of their supplier.

The spokeswoman admitted: "It makes no difference who the fuel supplier is."

So why ask for information that, in the wrong hands, could be misused? Why ask for information that is not necessary to do the job?

I was told: "It can be difficult to have different letters for all the different projects we are involved in.

"It's a standard letter that applies to 95 per cent of people."

Additionally, she said, the information could be used to find out if extra help was available from other sources.